There are two species of Cadulus that can be collected from Barkley Sound, although it takes some effort. Both may be collected from Sarita Bay which has a very deep "hole" in it. They two species are found together.
Cadulus californicus has a robust shell which is not translucent.
Cadulus tolmiei has a thinner, haline shell which is almost transparent.
The two species appear to have different diets, but that needs to be more fully investigated.